1. Field of the Invention
The invention pertains to a circuit arrangement for signal and information conversion between analog junction lines and digital terminal devices in communications exchanges. In particular the invention concerns an arrangement wherein decentralized control devices are provided in order to process and pass on switching criteria and codes received and sent to the analog junction line, both inside and outside of the audio frequency band.
2. Prior Art
A process for controlling switching codes and switching states on junction lines is known from DE 29 19 617 - Poehlchen (Nov. 20, 1980). The document discloses a decentralized control which serves several junction lines and controls switching codes lying outside the audio frequency band. The switching codes are received and transmitted via the junction line. This peripheral control device works with a scanning device and memory in which junction states and properties of the respective junction lines are stored in each case. The control of audio signals to be transmitted and the evaluation of audio frequencies received cannot be performed by such a control device.
DE 30 14 572 - Burkart et al (Oct. 29, 1981) discloses a circuit arrangement for transmitting low-frequency signals on junction lines in telephone exchanges. Matrix-like coupling components are provided with which centrally generated signals lying within the audio frequency band are switched onto the junction line. A decentralized control is provided in each case for this purpose which serves several communications lines. Switching codes lying outside the audio frequency band cannot be controlled with this circuit arrangement.